Having played the best tennis of his life over the past 10 months, the 28-year-old Swiss player made another statement by beating David Ferrer on Friday to reach the semifinals in his first appearance at the ATP World Tour Finals.

"It's certainly a dream season," the seventh-seeded Wawrinka said after rallying to beat David Ferrer 6-7 (3), 6-4, 6-1 in his final round-robin match. "I started as the world No. 17, I then reached my first quarters at the French Open, I made it to U.S. Open semis and I'm now doing well at the Finals. It's magic."

Wawrinka still had a nervous wait because he needed Rafael Nadal to beat Thomas Berdych in the late match in order to advance. The top-ranked Spaniard had already clinched a place in the semis but didn't falter, winning 6-4, 1-6, 6-3 to finish the group stage with a 3-0 record.

The 28-year-old Wawrinka has long been known for his natural talent and formidable one-handed backhand, but has spent most of his career in the shadow of Swiss countryman Roger Federer and was beginning to be seen as a perennial underachiever.

That has changed this season, after appointing Magnus Norman as his coach in April and working on his confidence and mental strength.

The partnership immediately paid off, as Wawrinka beat Ferrer to win a tournament in Oeiras, Portugal, before reaching the final of the Madrid Masters. The Swiss defeated Richard Gasquet at the French Open then grabbed victories over Tomas Berdych and Andy Murray en route to his first Grand Slam semifinal at the U.S. Open.

"It's a lot of small things that make huge difference," Wawrinka said about Norman's help. "But for sure I think this year the most important was my self-confidence on the court. Now, when I come on the court, even against (Tomas) Berdych, against Rafa (Nadal), against Ferrer today, I know that I can beat them. That's already a big step ahead."

Against Ferrer, Wawrinka hit 35 winners, including 12 aces, to clinch his second win at the elite year-end tournament.

Nadal just needed to claim a set against Berdych to be guaranteed of first place in Group A and lost his grip on the match in the second set, dropping his serve twice. However, Nadal made the decisive break in the eighth game of the decider after Berdych double-faulted twice.

"I wish him a good holiday and good luck for the Davis Cup," Nadal said of Berdych, who will be playing in next week's Davis Cup final between defending champion Czech Republic and Novak Djokovic's Serbia in Belgrade. "In the second set he played great, it was very difficult to stop him."

Defending champion Novak Djokovic has won Group B — meaning he'll play Wawrinka in the last four — and the winner of Saturday's match between Juan Martin del Potro and Roger Federer will face Nadal in the semifinals.

"It's an amazing week for me," said Wawrinka, who has claimed nine victories over Top 10 players this season. "I had to win against Tomas Berdych, David Ferrer, I lost a tough one against Nadal. At the ATP World Tour Finals, it was quite a good level for me. That's the most important."

After spending his whole career in the shadow of Federer, Wawrinka now has a chance to finish ahead the 17-time Grand Slam winner in the year-end rankings.

"But people should not expect me to win Grand Slam titles in the coming years, it's not as simple as that," Wawrinka said. "My main goal next season will be to keep the same level."

Serving hard and varying his play nicely, Wawrinka had the upper hand early on against Ferrer and broke for a 4-2 lead before comfortably holding serve in the next game. But the seventh-seeded debutant made three unforced errors when serving for the set, and Ferrer then used an aggressive net game to win four consecutive games, including one that lasted 14 minutes

The Spaniard's excellent spell abruptly ended in the next game when Wawrinka took his serve at love to force a tiebreaker.

Ferrer, the 2009 runner-up, jumped to a 4-0 lead before his opponent's 29th error of the match gave him three set points. Following another long exchange from the baseline, Wawrincka missed a forehand to lose the set.

Wawrinka looked frustrated but it was soon Ferrer's turn to wobble, with the third-seeded Spaniard making three unforced errors including his first double-fault of the match in the third game of the second set as he dropped serve and whacked his racket against the floor in anger. This time, Wawrinka held his serve to level the match.

Two unforced errors by Ferrer in the first game of the decider gave Wawrinka an early break, and the U.S. Open semifinalist hit three aces in the next game for a 2-0 lead. Wawrinka broke again for a 4-1 lead and closed out the match with a backhand after Ferrer misplayed an easy volley.